How to tell GPU new data is in memory?

Accelerated Computing CUDA CUDA Programming and Performance
1

I am designing a system that has a UDP server reading UDP data packets then passing the data to a GPU.
I am using a K20X GPU and dual Xeon system, CUDA 7.

I am trying to find a way to signal the GPU when a frame is written into page locked memory.

Can anyone point me in the direction of a solution?

Thanks.

2

Normally this would be via a kernel launch. Write the data, launch the kernel.

Presumably then you are talking about some method using persistent threads/persistent kernels:

[url]http://on-demand.gputechconf.com/gtc/2012/presentations/S0157-Persistent-Threads-Style-Programming-Model-for-GPU-Computing.pdf[/url]

In that case, you would need a semaphore that the GPU persistent master thread is polling. The semaphore would also be in mapped memory, and the host would write the semaphore after filling in the data packet(s). The GPU persistent master thread would then “signal” other threads/threadblocks to begin processing the packet(s). In the case of CUDA Dynamic Parallelism, this could be conceptually simplified by having the GPU master thread, once the semaphore is detected, launch child kernels to process the packet(s). However you may not want to follow this approach for performance (in particular, latency) reasons.

3

Thanks. The paper gave me some insight into the problem.